UW’s Stratospheric Research Using Balloons is Longest Continuous in the World

November 20, 2012 — For more than 40 years, University of Wyoming faculty have
been launching research balloons where the skies are not cloudy all day, giving
UW the distinction of being the nation’s research institution with the longest
running program for measuring stratospheric aerosol.

Since 1971, when then-UW physics professors Jim Rosen and
Dave Hofmann launched their first research balloon into the heavens, university
researchers and graduate students have looked to the sky for answers about Earth’s
climate and ozone levels.

The National Scientific Balloon Facility (NSBF) in Texas and
the Center for National Studies of Space (CNES) in France also use balloons for
stratospheric research, but their flights are infrequent. NSBF and CNES fly
their own balloons, but rely on other scientists for the measuring instruments.
UW, by contrast, typically makes six
flights a year, or once every two months, and uses its own measuring equipment,
Deshler says.

Even though this particular type of research using balloons began
in the late 1950s in South Dakota, UW has been measuring stratospheric aerosol longer
than anyone else, Deshler says. Facilities in Brazil, Germany and Hawaii have
conducted stratospheric aerosol measurements -- using Lidar -- since 1974 and
continue to this day. Another, in Hampton, Va., also began using Lidar for such
experiments in 1974, but stopped its program around 2003. Lidar, an acronym for
light detection and ranging, is an optic remote sensing technology.

“We make (aerosol particle) measurements with balloons.
Other researchers measure this using Lidar and satellites,” Deshler says. “(The
University of) Wyoming is unique in that we started this earlier than
anyone else and continued it since. We are making particle size and
concentration measurements (of aerosol), which no one else makes.”

God’s country is
ideal

There are reasons ballooning is not used widely for such
research. One, it is expensive and, two, the places where it can be done are
limited. Deshler says European countries once used balloons for such research
in Europe, but don’t any more as population densities have increased there. It
is not feasible to conduct such research on the U.S. East Coast, because the
balloons would end up in the ocean, he says.

Wyoming, however, is ideal for such research because it has
the lowest population of any state and there are many days with clear skies,
which keeps the balloons visible to aircraft. Winds, when coming from the west-northwest
or southwest, are correct for the balloons’ trajectory, which keeps them
away from airspace over Denver International Airport and away from the
mountains.

“It’s kind of serendipity that they (Rosen and Hofmann) came
to Wyoming,” says Deshler, who became involved with the aerosol measurement research at UW as a post-doctoral
researcher in 1988. He took over as principal investigator in 1991, when Hofmann
retired. “We’ve been doing this for more than 40 years now.”

A continual funding source -- courtesy of the National
Science Foundation (NSF) -- has been a key element for this research to endure
without interruption.

“NSF has been a funder from day one,” Deshler says
appreciatively.

Over the years, NASA and the Naval Research Laboratory also
have funded UW’s aerosol measurement research, he says.

Research highlights

Over time, there have been a number of scientific highlights
in Laramie. Aerosol particles -- in size and number -- showed spikes in the
stratosphere, due primarily to volcanic events. Deshler points to a series of black-and-red
colored charts -- depicting normal and volcanic-effected aerosol levels – which
are part of a reference book chapter in which he was the lead author.

The chapter, which reviewed stratospheric aerosol trends
from 1971-2004, was part of a reference book titled “SPARC Assessment of
Stratospheric Aerosol Properties.”

SPARC stands for “Stratospheric Processes and Their Role in
Climate” and is a project of the World Meteorological Organization,
International Council for Science and the International Ozone Commission.

With enthusiasm, Deshler rattled off stratospheric changes
due to the El Chichon eruption in southeastern Mexico in 1982; the change in
non-volcanic aerosol in 1988 (dating before the Pinatubo eruption); and the
largest eruption of a volcano -- Pinatubo in 1991 -- during the last 50 years.

“What’s exciting about the record is that we see the impacts
on the stratosphere from large volcanic eruptions throughout the world, and can
look for less dramatic effects on the stratosphere in the absence of volcanoes,”
he says.

These eruptions are important for analyzing short-term
regional and global effects on climate from enhanced stratospheric aerosol
loading, according to information in Deshler’s book chapter.

One, measurements show whether there have been changes in
the material in the stratosphere and the source of material that reaches the
stratosphere. These can range from aerosol clouds from volcanoes, natural
emissions, biological emissions produced by fires or sea plankton, bacterial
emissions, and sulfur byproducts created by coal combustion, Deshler says.

Second, stratospheric aerosol can do two things relevant to
radiation. The particles scatter sunlight back to space, which has a cooling
effect. The aerosol also can absorb infrared radiation from the Earth, which
has a local warming effect, he says.

“The ozone is controlled, to some extent, by particles in
the atmosphere, particularly when volcanic activity is at a minimum,” he says.

And fourth, a number of satellites record various
measurements that require knowledge of the stratospheric aerosol size distribution.
Some satellites, which measure molecular concentrations, have to make
assumptions about the atmospheric aerosol to quantify their results, Deshler
says.

“Mother Nature keeps dealing us hands that are interesting
in their own right,” Deshler says. “We, as scientists, have to look at why aerosol
measurements are important.”

Photo:Terry Deshler (in green jacket), a UW professor of
atmospheric science, and his team technician, push the balloon launcher away
from the facility and toward the tarmac.